Add doc comments

[mappum]

This PR adds basic doc comment coverage to some missing places.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 22.22222% with 7 lines in your changes missing coverage. Please review.

Project coverage is 94.17%. Comparing base (c595a8d) to head (45f3f99). Report is 5 commits behind head on develop.

Files with missing lines	Patch %	Lines
src/merk/snapshot.rs	0.00%	4 Missing :warning:
src/merk/mod.rs	0.00%	3 Missing :warning:

Additional details and impacted files

[](https://app.codecov.io/gh/turbofish-org/merk/pull/80?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=turbofish-org) ```diff @@ Coverage Diff @@ ## develop #80 +/- ## =========================================== + Coverage 94.07% 94.17% +0.10% =========================================== Files 27 27 Lines 5449 5443 -6 =========================================== Hits 5126 5126 + Misses 323 317 -6 ``` | [Files with missing lines](https://app.codecov.io/gh/turbofish-org/merk/pull/80?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=turbofish-org) | Coverage Δ | | |---|---|---| | [src/proofs/query/map.rs](https://app.codecov.io/gh/turbofish-org/merk/pull/80?src=pr&el=tree&filepath=src%2Fproofs%2Fquery%2Fmap.rs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=turbofish-org#diff-c3JjL3Byb29mcy9xdWVyeS9tYXAucnM=) | `98.83% <100.00%> (ø)` | | | [src/proofs/tree.rs](https://app.codecov.io/gh/turbofish-org/merk/pull/80?src=pr&el=tree&filepath=src%2Fproofs%2Ftree.rs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=turbofish-org#diff-c3JjL3Byb29mcy90cmVlLnJz) | `94.21% <ø> (ø)` | | | [src/test\_utils/mod.rs](https://app.codecov.io/gh/turbofish-org/merk/pull/80?src=pr&el=tree&filepath=src%2Ftest_utils%2Fmod.rs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=turbofish-org#diff-c3JjL3Rlc3RfdXRpbHMvbW9kLnJz) | `84.42% <ø> (ø)` | | | [src/tree/ops.rs](https://app.codecov.io/gh/turbofish-org/merk/pull/80?src=pr&el=tree&filepath=src%2Ftree%2Fops.rs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=turbofish-org#diff-c3JjL3RyZWUvb3BzLnJz) | `99.16% <ø> (ø)` | | | [src/merk/mod.rs](https://app.codecov.io/gh/turbofish-org/merk/pull/80?src=pr&el=tree&filepath=src%2Fmerk%2Fmod.rs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=turbofish-org#diff-c3JjL21lcmsvbW9kLnJz) | `90.14% <0.00%> (+0.47%)` | :arrow_up: | | [src/merk/snapshot.rs](https://app.codecov.io/gh/turbofish-org/merk/pull/80?src=pr&el=tree&filepath=src%2Fmerk%2Fsnapshot.rs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=turbofish-org#diff-c3JjL21lcmsvc25hcHNob3QucnM=) | `9.01% <0.00%> (+0.21%)` | :arrow_up: | [](https://app.codecov.io/gh/turbofish-org/merk/pull/80?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=turbofish-org)